scholarly journals Low-Cost Graphene-Based Digital Microfluidic System

Micromachines ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 880
Author(s):  
Mohamed Yafia ◽  
Amir M. Foudeh ◽  
Maryam Tabrizian ◽  
Homayoun Najjaran
Keyword(s):  
Point Of Care ◽  
Low Cost ◽  
High Specificity ◽  
Microfluidic System ◽  
Contact Angles ◽  
Electrode Arrays ◽  
Laser Scribing ◽  
Nucleotide Mismatch ◽  
Accessible Point ◽  
Digital Microfluidic

In this work, the laser-scribing technique was used as a low-cost, rapid and facile method for fabricating digital microfluidic (DMF) systems. Laser-scribed graphene (LSG) electrodes are directly synthesized on flexible substrates to pattern the DMF electrode arrays. This facilitates the DMF electrodes’ fabrication process by eliminating many microfabrication steps. An electrowetting test was performed to investigate the effectiveness of the LSG DMF electrodes in changing the contact angles of droplets. Different DMF operations were successfully performed using the proposed LSG DMF chips in both open and closed DMF systems. The quality and output resolution were examined to assess the performance of such patterned electrodes in the DMF systems. To verify the efficacy of the LSG DMF chips, a one-step direct assay for the detection of Legionellapneumophila deoxyribonucleic acid (DNA) was performed on the chip without the need for any washing step. The high specificity in distinguishing a single-nucleotide mismatch was achieved by detecting target DNA concentrations as low as 1 nM. Our findings suggest that the proposed rapid and easy fabrication method for LSG DMF electrodes offers a great platform for low-cost and easily accessible point-of-care diagnostic devices.

scholarly journals A Low-Cost, Disposable and Portable Inkjet-Printed Biochip for the Developing World

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3593
Author(s):  
Kushal Joshi ◽  
Vanessa Velasco ◽  
Rahim Esfandyarpour
Keyword(s):  
Low Income ◽  
Capital Investment ◽  
Point Of Care ◽  
Low Cost ◽  
Low Income Countries ◽  
Electrode Arrays ◽  
Electrowetting On Dielectric ◽  
Biochemical Assays ◽  
Fabrication Procedure ◽  
Digital Microfluidic

Electrowetting on dielectric-based digital microfluidic platforms (EWOD-DMF) have a potential to impact point-of-care diagnostics. Conventionally, EWOD-DMF platforms are manufactured in cleanrooms by expert technicians using costly and time consuming micro-nanofabrication processes such as optical lithography, depositions and etching. However, such high-end microfabrication facilities are extremely challenging to establish in resource-poor and low-income countries, due to their high capital investment and operating costs. This makes the fabrication of EWOD-DMF platforms extremely challenging in low-income countries, where such platforms are most needed for many applications such as point-of-care testing applications. To address this challenge, we present a low-cost and simple fabrication procedure for EWOD-DMF electrode arrays, which can be performed anywhere with a commercial office inkjet printer without the need of expensive cleanroom facilities. We demonstrate the utility of our platform to move and mix droplets of different reagents and physiologically conductive buffers, thereby showing its capability to potentially perform a variety of biochemical assays. By combining our low-cost, inkjet-printed EWOD-DMF platform with smartphone imaging technology and a compact control system for droplet manipulation, we also demonstrate a portable and hand-held device which can be programmed to potentially perform a variety of biochemical assays.

scholarly journals Electroanalytical Biosensors for Circulating Tumor DNA Detection—A Brief Review

2021 ◽  
Author(s):  
Zhijia Peng ◽  
Xiaogang Lin ◽  
Weiqi Nian ◽  
Xiaodong Zheng ◽  
Jayne Wu
Keyword(s):  
Real Time ◽  
Point Of Care ◽  
Low Cost ◽  
High Sensitivity ◽  
High Specificity ◽  
Circulating Tumor Dna ◽  
Minimal Invasive ◽  
Diagnosis And Treatment ◽  
Detection Technology ◽  
Tumor Dna

Early diagnosis and treatment have always been highly desired in the fight against cancer, and detection of circulating tumor DNA (ctDNA) has recently been touted as highly promising for early cancer screening. Consequently, the detection of ctDNA in liquid biopsy gains much attention in the field of tumor diagnosis and treatment, which has also attracted research interest from the industry. However, traditional gene detection technology is difficult to achieve low cost, real-time and portable measurement of ctDNA. Electroanalytical biosensors have many unique advantages such as high sensitivity, high specificity, low cost and good portability. Therefore, this review aims to discuss the latest development of biosensors for minimal-invasive, rapid, and real-time ctDNA detection. Various ctDNA sensors are reviewed with respect to their choices of receptor probes, detection strategies and figures of merit. Aiming at the portable, real-time and non-destructive characteristics of biosensors, we analyze their development in the Internet of Things, point-of-care testing, big data and big health.

scholarly journals Whole Blood Immunoassay Based on Centrifugal Bead Sedimentation

2011 ◽  
Vol 57 (5) ◽  
pp. 753-761 ◽  
Author(s):  
Ulrich Y Schaff ◽  
Greg J Sommer
Keyword(s):  
Whole Blood ◽  
Single Channel ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Low Cost ◽  
Microfluidic System ◽  
Blood Samples ◽  
Reactive Protein ◽  
Immunoassay Technique ◽  
Microfluidic Immunoassay

BACKGROUND Centrifugal “lab on a disk” microfluidics is a promising avenue for developing portable, low-cost, automated immunoassays. However, the necessity of incorporating multiple wash steps results in complicated designs that increase the time and sample/reagent volumes needed to run assays and raises the probability of errors. We present proof of principle for a disk-based microfluidic immunoassay technique that processes blood samples without conventional wash steps. METHODS Microfluidic disks were fabricated from layers of patterned, double-sided tape and polymer sheets. Sample was mixed on-disk with assay capture beads and labeling antibodies. Following incubation, the assay beads were physically separated from the blood cells, plasma, and unbound label by centrifugation through a density medium. A signal-laden pellet formed at the periphery of the disk was analyzed to quantify concentration of the target analyte. RESULTS To demonstrate this technique, the inflammation biomarkers C-reactive protein and interleukin-6 were measured from spiked mouse plasma and human whole blood samples. On-disk processing (mixing, labeling, and separation) facilitated direct assays on 1-μL samples with a 15-min sample-to-answer time, <100 pmol/L limit of detection, and 10% CV. We also used a unique single-channel multiplexing technique based on the sedimentation rate of different size or density bead populations. CONCLUSIONS This portable microfluidic system is a promising method for rapid, inexpensive, and automated detection of multiple analytes directly from a drop of blood in a point-of-care setting.

scholarly journals Loop-Mediated Isothermal Amplification as Point-of-Care Diagnosis for Neglected Parasitic Infections

2020 ◽  
Vol 21 (21) ◽  
pp. 7981
Author(s):  
Catalina Avendaño ◽  
Manuel Alfonso Patarroyo
Keyword(s):  
Neglected Tropical Diseases ◽  
Point Of Care ◽  
Low Cost ◽  
High Specificity ◽  
World Health Organisation ◽  
Isothermal Amplification ◽  
World Health ◽  
Parasitic Infections ◽  
River Blindness ◽  
Loop Mediated Isothermal Amplification

The World Health Organisation (WHO) has placed twenty diseases into a group known as neglected tropical diseases (NTDs), twelve of them being parasitic diseases: Chagas’ disease, cysticercosis/taeniasis, echinococcosis, food-borne trematodiasis, human African trypanosomiasis (sleeping sickness), leishmaniasis, lymphatic filariasis, onchocerciasis (river blindness), schistosomiasis, soil-transmitted helminthiasis (ascariasis, hookworm, trichuriasis), guinea-worm and scabies. Such diseases affect millions of people in developing countries where one of the main problems concerning the control of these diseases is diagnosis-based due to the most affected areas usually being far from laboratories having suitable infrastructure and/or being equipped with sophisticated equipment. Advances have been made during the last two decades regarding standardising and introducing techniques enabling diagnoses to be made in remote places, i.e., the loop-mediated isothermal amplification (LAMP) technique. This technique’s advantages include being able to perform it using simple equipment, diagnosis made directly in the field, low cost of each test and the technique’s high specificity. Using this technique could thus contribute toward neglected parasite infection (NPI) control and eradication programmes. This review describes the advances made to date regarding LAMP tests, as it has been found that even though several studies have been conducted concerning most NPI, information is scarce for others.

scholarly journals A Single-Bead-Based, Fully Integrated Microfluidic System for High-Throughput CD4+T Lymphocyte Enumeration

2017 ◽  
Vol 23 (2) ◽  
pp. 134-143 ◽  
Author(s):  
Xianbo Qiu ◽  
Junhui Zhang ◽  
Shisong Gong ◽  
Dong Wang ◽  
Shan Qiao ◽  
...  
Keyword(s):  
T Lymphocyte ◽  
High Throughput ◽  
Point Of Care ◽  
Low Cost ◽  
Ccd Camera ◽  
Microfluidic System ◽  
Magnetic Control ◽  
Magnetic Actuation ◽  
Fully Integrated ◽  
Single Bead

A single-bead-based, fully integrated microfluidic system has been developed for high-throughput CD4+T lymphocyte enumeration at point-of-care testing. Instead of directly counting CD4+T lymphocytes, CD4+T lymphocyte enumeration is achieved by quantitatively detecting CD4 antigen from the lysed blood sample with a functionalized polycarbonate single bead based on chemiluminescence. To implement the sandwiched chemiluminescence immunoassay with reduced nonspecific binding, a streamlined microfluidic chip with multiple reaction chambers is developed to allow each reaction step to be completed in an independent chamber where reagent is pre-stored. With simple magnetic control, the single bead with an embedded ferrous core can be consecutively transported between each of two adjacent chambers for different reactions. Meanwhile, enhanced mixing can be achieved by moving the single bead back and forth inside one chamber with magnetic actuation. High-throughput detection can be performed when a linear actuation stage is adopted to introduce synchronous magnetic control to multiple single beads in parallel microfluidic chips. A sensitive charge-coupled device (CCD) camera is adopted for high-throughput chemiluminescence detection from multiple single beads. Experimental results show that with the fully integrated microfluidic system, easy-to-operate, accurate, low-cost, immediate, and high-throughput CD4+T lymphocyte enumeration can be successfully achieved at resource-poor settings.

scholarly journals Microfluidic system for screening disease based on physical properties of blood

Bioimpacts ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 141-150
Author(s):  
Siddharth Singh Yadav ◽  
Basant Singh Sikarwar ◽  
Priya Ranjan ◽  
Rajiv Janardhanan
Keyword(s):  
Physical Properties ◽  
Large Scale ◽  
One Health ◽  
Point Of Care ◽  
Low Cost ◽  
Microfluidic System ◽  
Middle Income ◽  
Blood Samples ◽  
Resource Limited ◽  
Automated Classifier

Introduction: A key feature of the 'One Health' concept pertains to the design of novel point of care systems for largescale screening of health of the population residing in resource-limited areas of low- and middle-income countries with a view to obtaining data at a community level as a rationale to achieve better public health outcomes. The physical properties of blood are different for different samples. Our study involved the development of an innovative system architecture based upon the physical properties of blood using automated classifiers to enable large-scale screening of the health of the population living in resource-limited settings. Methods: The proposed system consisted of a simple, robust and low-cost sensor with capabilities to sense and measure even the minute changes in the physical properties of blood samples. In this system, the viscosity of blood was derived from a power-law model coupled with the Rabinowitsch-Mooney correction for non-Newtonian shear rates developed in a steady laminar Poiseuille flow. Surface tension was measured by solving the Young-Laplace equation for pendant drop shape hanging on a vertical needle. An anticipated outcome of this study would be the development of a novel automated classifier based upon the rheological attributes of blood. This automated classifier would have potential application in evaluating the health status of a population at regional and global levels. Results: The proposed system was used to measure the physical properties of various samples like normal, tuberculous and anemic blood samples. The results showed that the physical properties of these samples were different as compared to normal blood samples. The major advantage of this system was low-cost, as well as its simplicity and portability. Conclusion: In this work, we proposed making a case for the validation of a low-cost version of a microfluidic system capable of scanning large populations for a variety of diseases as per the WHO mandate of "One Health".

scholarly journals Design and Experimental Investigation of a Novel Spiral Microfluidic Chip to Separate Wide Size Range of Micro-Particles Aimed at Cell Separation

2021 ◽  
Author(s):  
Seyed Ali Tabatabaei ◽  
Mohammad Zabetian targhi
Keyword(s):  
Cell Separation ◽  
Point Of Care ◽  
Low Cost ◽  
Diagnostic System ◽  
Average Diameter ◽  
Microfluidic System ◽  
Microfluidic Chips ◽  
Blood Samples ◽  
Micro Particles ◽  
User Friendly

Abstract BackgroundIsolation of microparticles and biological cells on microfluidic chips has received considerable attention due to their applications in numerous areas such as medical and engineering fields. Microparticles separation are of great importance in bioassays owing to the need for a smaller sample and device size, and lower manufacturing costs. In this study, we first explain the concepts of separation and microfluidic science along with their applications in the medical sciences, and then, a conceptual design of a novel inertial microfluidic system is proposed and analyzed. The PDMS spiral microfluidic device was fabricated, and its effects on the separation of particles with sizes similar to biological particles were experimentally analyzed. This separation technique can be used in the process of separating cancer cells from the normal ones in the blood samples.ResultsThese components required for testing were selected, assembled, and finally, a very affordable microfluidic kit was provided. Different experiments were designed, and the results were analyzed using appropriate software and methods. Separator system tests with polydisperse hollow glass particles (diameter 2-20 µm), and monodisperse Polystyrene particles (diameter 5,15 µm), and the results exhibit an acceptable chip performance with 86 percent of efficiency for both monodisperse particles and polydisperse particles. The microchannel collects particles with an average diameter of 15.8 μm, 9.4 μm, and 5.9 μm at the Proposed reservoirs. ConclusionThis chip can be integrated into a more extensive point-of-care diagnostic system to test blood samples, and it could be said Based on the results of the experiments, this low-cost and user-friendly setting can be used for a variety of microparticle separation programs such as cell separation in biological assays.

scholarly journals Suppressing Non-Specific Binding of Proteins onto Electrode Surfaces in the Development of Electrochemical Immunosensors

Biosensors ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 15 ◽  
Author(s):  
Jesús Contreras-Naranjo ◽  
Oscar Aguilar
Keyword(s):  
Solid Phase ◽  
Specific Binding ◽  
Point Of Care ◽  
Low Cost ◽  
Electrochemical Techniques ◽  
High Specificity ◽  
Electrode Surfaces ◽  
Solid Phase Immunoassay ◽  
Electrochemical Immunosensors ◽  
Complex Phenomena

Electrochemical immunosensors, EIs, are systems that combine the analytical power of electrochemical techniques and the high selectivity and specificity of antibodies in a solid phase immunoassay for target analyte. In EIs, the most used transducer platforms are screen printed electrodes, SPEs. Some characteristics of EIs are their low cost, portability for point of care testing (POCT) applications, high specificity and selectivity to the target molecule, low sample and reagent consumption and easy to use. Despite all these attractive features, still exist one to cover and it is the enhancement of the sensitivity of the EIs. In this review, an approach to understand how this can be achieved is presented. First, it is necessary to comprise thoroughly all the complex phenomena that happen simultaneously in the protein-surface interface when adsorption of the protein occurs. Physicochemical properties of the protein and the surface as well as the adsorption phenomena influence the sensitivity of the EIs. From this point, some strategies to suppress non-specific binding, NSB, of proteins onto electrode surfaces in order to improve the sensitivity of EIs are mentioned.

scholarly journals Loop-Mediated Isothermal Amplification (LAMP) for the Diagnosis of Zika Virus: A Review

Viruses ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 19 ◽  
Author(s):  
Severino Jefferson Ribeiro da Silva ◽  
Keith Pardee ◽  
Lindomar Pena
Keyword(s):  
Zika Virus ◽  
Molecular System ◽  
Point Of Care ◽  
Low Cost ◽  
Quantitative Polymerase Chain Reaction ◽  
High Specificity ◽  
Isothermal Amplification ◽  
Loop Mediated Isothermal Amplification ◽  
Freeze Dried ◽  
Polymerase Chain

The recent outbreak of Zika virus (ZIKV) in the Americas and its devastating developmental and neurological manifestations has prompted the development of field-based diagnostics that are rapid, reliable, handheld, specific, sensitive, and inexpensive. The gold standard molecular method for lab-based diagnosis of ZIKV, from either patient samples or insect vectors, is reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The method, however, is costly and requires lab-based equipment and expertise, which severely limits its use as a point-of-care (POC) tool in resource-poor settings. Moreover, given the lack of antivirals or approved vaccines for ZIKV infection, a POC diagnostic test is urgently needed for the early detection of new outbreaks and to adequately manage patients. Loop-mediated isothermal amplification (LAMP) is a compelling alternative to RT-qPCR for ZIKV and other arboviruses. This low-cost molecular system can be freeze-dried for distribution and exhibits high specificity, sensitivity, and efficiency. A growing body of evidence suggests that LAMP assays can provide greater accessibility to much-needed diagnostics for ZIKV infections, especially in developing countries where the ZIKV is now endemic. This review summarizes the different LAMP methods that have been developed for the virus and summarizes their features, advantages, and limitations.

A Complete Routing Simulator for Digital Microfluidic Biochip

2019 ◽  
Vol 10 (2) ◽  
pp. 70-85
Author(s):  
Rupam Bhattacharya ◽  
Pranab Roy ◽  
Hafizur Rahaman
Keyword(s):  
Significant Contribution ◽  
Arrival Time ◽  
Heuristic Algorithms ◽  
Point Of Care ◽  
Low Cost ◽  
Clinical Applications ◽  
Routing Algorithms ◽  
Point Of Care Diagnostics ◽  
Digital Microfluidic ◽  
Reconfigurable Device

Microfluidic technology, as well as digital microfluidic biochips (DMFBs), have had a very significant contribution in the field of medical bio-chemistry such as point-of-care diagnostics, environmental monitoring, DNA sequencing, etc. DMFBs are low cost, highly flexible and reconfigurable device that makes it so advantageous in clinical applications. The routing of a nano-liter volume of droplets is very important and is a critical operation in DMFB. Complex heuristic algorithms have been developed for droplet routing. Proper simulation is very essential to measure the effectiveness of these algorithms. In this work, the authors develop a complete routing simulator for both homogeneous and heterogeneous type droplets. The proposed routing simulator graphically represents the routing operation of droplets in DMFB and display the measurement of all parameters of routing algorithms such as latest arrival time, average arrival time, number of cells used, and the total number of contaminations. The proposed simulator was executed on suit I and III benchmark testbenches.

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